Composite ball joint



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Sept; 22, 1959 L. w. ALEXANDER COMPOSITE BALL JOINT Filed May 16,- 1958IN VEN TOR.

United States Patent COMPOSITE BALL JOINT Lewis W. Alexander,Northville, Mich., assignor to Halex Corporation, Detroit, Mich., acorporation of Michigan Application May 16, 1958, Serial No. 735,777 9Claims. (Cl. 287-87) This invention relates to ball joints and, inparticular, to composite ball joints, the components of which are madeup of different materials.

One object of this invention is to provide a composite ball jointcomposed in part of metal and in part of plastic material, such as thepolymeric amide plastic known commercially as nylon, having greaterresistance to wear and a smoother and softer action than prior balljoints,

particularly those used for front and rear wheel suspensions onautomobiles.

Another object is to provide a composite ball joint of the foregoingcharacter wherein the socket members in which the ball oscillates arequickly and easily adjusted by the use of constantly available tools,such as ordinary wrenches.

Another object is to provide a composite ball joint of the foregoingcharacter which is adaptable either to a ball on the end of a rod or toa ball intermediate the ends of the rod, as for automobile front wheelsuspension.

Another object is to provide a composite ball joint of the foregoingcharacter wherein the socket members are resiliently mounted by means ofspring portions either integral with the socket members or separatetherefrom.

Another object is to provide a composite ball joint of the foregoingcharacter wherein the socket members are resiliently supported not onlyfor motion in the direction of the axis of the rod on which the ball ismounted but also in a direction transversely thereto.

Another object is to provide a composite ball joint of the foregoingcharacter wherein the socket members are resiliently mounted betweencupped spring washers and are separated from one another by a shim orshims, thereby precisely controlling the tightness of fit of the ballwithin the socket members and also enabling the controlling of this fitindependently of the spring load imposed upon the ball by the springwashers, the spring load being thus capable of being held substantiallyconstant, without tightening or loosening of the ball on account of wearor for other reasons.

Other objects and advantages of the invention will become apparentduring the course of the following description of the accompanyingdrawings, wherein:

Figure 1 is a top plan view of a composite ball joint employing asynthetic plastic ball member, according to one form of the invention,shown for purposes of example as applied to an automobile front Wheelsuspension;

Figure 2 is a central vertical section, with the rod head partly in sideelevation, taken along the line 2-2 in Figure 1;

Figure 3 is a view similar to Figure 2, of a modified ball jointemploying cupped spring washers to exert resilient force on the socketmembers, with the ball member shown in side elevation;

Figure 4 is a central vertical section through a further modified balljoint wherein the synthetic plastic ball is mounted on a roughenedportion of a rod intermediate the ends thereof, as exemplified by anautomobile rear wheel suspension;

Figure 5 is a view similar'to Figure 4 of a further modified ball jointas exemplified by an automobile rear wheel suspension wherein thesynthetic plastic ball is iceformed around an intermediate enlargementon the rod; and

Figure 6 is a view similar to Figure 3 of a still further modified balljointemploying cupped spring washers to exert resilient force on thesocket members, with the ball member shown partly in section and partlyin side elevation.

This is a continuation-in-part of my copending application Serial No.586,016, filed May 21, 1956, for Ball Joint, now Alexander Patent No.2,862,740, issued December 2, 1958.

Referring to the drawings in detail, Figures 1 and 2 show a compositeball joint, generally designated 10, according to one form of theinvention as consisting generally of a rod and ball unit 12 resilientlymounted in a socket structure, generally designated 14, one element ofwhich consists of a sheet metal member 16 forming a part of the machine,such as an automobile front wheel suspension, in which the ball joint 10is used. The rod and ball unit 12, as its name suggests, consists of arod 18 of steel or the like having a head or similar enlargement 20 onthe upper end thereof, the head 20 being shown merely for purposes ofexample as bulbous and not necessarily spherical, with peripheral flutesor grooves 22 disposed parallel to the axis of the rod 18. The head 20is formed in any suitable manner, such as by the so-called cold-headingprocess, the exact manner of formation being beyond the scope of thepresent invention.

Substantially surrounding the head 20 and the rod 18 attached thereto isa ball portion 24 of synthetic plastic material, such as the polymericamide plastic known commercially as nylon, and having a spherical outersurface 26. The rod and ball units ball portion 24 of Fig ures 1 and 2is formed by pressing suitable powdered synthetic plastic material, suchas, for example, polymeric amide around the head 2% and adjacent portionof the rod 18 in a mold in a suitable press (not shown) and sinteringthe assembly thus created in order to secure the ball portion 24 firmlyto the rod 18. The consequent shrinkage of the ball portion 24 incooling, because of the greater coefficient of expansion of thesynthetic plastic material than the steel of the rod 18 and its head 20increases the tenacity of adherence and grip between the ball port-ion24 and the rod 18 and its head 20.

The spherical convex surface 26 of the ball portion 24 slidably andoscillatably engages spherical concave surfaces 28 and 30 respectivelyof upper and lower socket units, generally designated 32 and 34respectively, preferably of resilient sheet steel. The upper socket unit32 is of nearly hemi-spherical extent with an interrupted upwardlyconcave integral peripheral flange 36 composed ofoircumferentially-spaced quadrant spring flange portions 38 extendingthrough a circular aperture 40 in the sheet metal member 16 and engagingthe lower surface 42 thereof (Figure 2).

Extending through the circumferential gaps 34 between the quadrantspring flange portions 38 are integral upturned lugs 46 engageable withthe cylindrical side walls 48 of the aperture 40 and disposedapproximately parallel to the axis of the aperture 40. The upturnedconcave quadrant spring flange portions 38 thus engage the sheet metalmember 16 and the aperture wall 48 substantially at right angles to oneanother so as to resiliently support and engage the upper socket member32 relatively to the sheet metal member 16 both axially andtransversely.

The lower socket member 34, in contrast to the upper socket member 32,is not approximately hemi-spherical, but is roughly in the form of azone of a hemisphere with a central aperture 50 of sufficiently largerdiameter than the rod 18 to allow the desired angle of rocking of therod 18 relatively to the axis of the upper socket member 32. The lowersocket member 34, like the upper socket member 32, is preferably ofresilient sheet steel 'but has a-s-ubstantially continuousdownwardly-concave annular flange 52 integral therewith and spaced ashort axial distance from the quadrant spring flange-portion 38 of'theinterrupted peripheral change 36 so as to provide an annular adjustmentspace'therebetween. The outer edge of the flange 52 engages the uppersurface 56 of a ring, generally designated 58, having a central aperture60 therein through which the cupped central portion 62 of the lowersocket member 34 extends downward, even as-the cupped central portion 64of the upper socket member 32 extends upward through the centralaperture 40 in the sheet metal member 16. The ring 58 and sheet thesheet metal member 16 a sufficient distance to exert sufiicient force onthe edges of the flange 52 and interrupted flange 36 so as toresiliently urge the upper and lower socket members 32 and 34 toward oneanother to provide the desired slipping engagement of their sphericalsurfaces 28 and 30 by the ball portion 24 on the head 20 of the rod 18.As a consequence, the rod and ball unit 12 is resiliently and yieldablysupported in the upper and lower socket units 32 and 34 in an axialdirection, and at the same time is yieldably supported in anapproximately radial transverse direction by the spring lug 46 actingagainst the side walls 48 of the aperture 40 in the sheet metal member16.

The modified composite ball joint, generally designated 70, shown inFigure 3 is generally similar to the composite ball joint of Figures 1and 2, insofar as the construction of the rod and ball unit 12 isconcerned, and also with respect to the construction of the sheet metalmember 16 and ring 58, hence similar parts are designated with the samereference numerals. The upper and lower socket members 72 and 74respectively differ slightly in construction from the upper and lowersocket members 32 and 34 respectively in that the axial force urgingthem toward one another and into engagement with the ball portion 24 isprovided by a pair of upper and lower cupped annular spring washers 76and 78 engaging the quadrant spring flange portion 80 of the uppercupped spherical socket member 72 and the continuous annular flange 82of the lower cupped zonal socket member 74. The flanges 80 and 82,instead of being concave, are approximately radial and flat, and areengaged by the inner portions of the annular cupped spring wash ers 76and 78 which have central apertures 84 and 86 respectively encirclingtheir respective socket members 72 and 74. The outer edge portions 88and 90 of the cupped annular spring washers 76 and 78 respectivelyengage the lower surface 42 of the sheetmetal member 16 and the uppersurface 56 of the ring 58 as abutments so that the spring force orresilience of the washers 76 and 78 is exerted in opposite directionsagainst the flanges 80 and 82 to urge the upper and lower socket members'74 in opposite directions against the spherical surface 26 of theplastic ball portion 24 of the rod and ball unit 12. The socket members72 and 74 have spherically-curved concave surfaces 92 and 94respectively enga-geable with the spherical surface 2 6 of the ballportion 24 and the upper socket member 72 also has upturned spring lugs96 disposed in the gaps 98 between the quadrant flange portions 80 so asto engage the side wall 48 of the central aperture 40 in the sheet metalmember 16. p v

The operation of the modified composite ball joint 70 of Figure 3 issimilar to that of the composite ball joint 10 of Figures 1 and 2, withtheexception of the fact-that the spring efiector urging the upper andlower socket nienibe'rs'72' and 74 toward one another is'brought' aboutby the action of the cupped spring washers 76 and '78, the adjustment ofwhich as to resilience is effected by the bolts 69. The resilientmounting of the ball joint, however, is elfected by the spring lug 96 inan approximately radial transverse'direction' in amanner similar to theaction of the spriiglugs 46 ofthe ball joint 10.

Thefurther modified composite ball joint, generally designated 100,shown in I Figure 4' employs -a"s"ocket structure 114 which-issubstantially the same in construction as' the socket structure 14 ofFigures 1 and 2 and similar parts are 'therefore similarly designatedwith reference numerals, differing only in the additional provision ofa'central aperture 102 in the upper socket-unit'32, similar to thecentral aperture 50 in the lower socket unit 34 thereof.The'additionalaperture 102 ismade necessary by the fact that the rod 166of the rod and ball unit 1080f the ball joint 100 extends through theupper socket unit 32 as well as through the lower socket unit 34, henceboth are provided with central apertures 102 and 50 respectively. Boththe upper and lower socket units of the socket structure 114 aretherefore of segment-shaped form instead of only the lower socket member34 being of segment-shaped form, as in the socket structure 14 ofFigures l and 2.

The rod'and ball unit'108 of Figure 4 has a roughened portion 112 formedintermediate the ends of the rod 106, such as by splining or groovingthis intermediate portion 112. The ball portion 116 of the rod and ballunit 1 0 8 with its spherical outer surface 118 is formed by pressingsuitable powdered synthetic plastic material, such as, for

i'example, polymeric amide plastic commercially known as nylon, aroundthe roughened portion 112 in a mold in a suitable press (not shown) andsintering the assembly 'thus created in order to secure the ball portion116 firmly to the rod 166. The consequent shrinkage of the ball portion116 in cooling, because of the greater coefiicient of expansion'of itssynthetic plastic material than the steel of the rod 106, increases thetenacity of adherence and grip between the ball portion 116 and the rod106.

In the use of the modified ball joint 100 of Figure 4, which is shown asapplied to the rear wheel suspension of an automobile, the rod 106 isadapted to oscillate at both its upper and lower ends within the upperand lower socket units 32 and 34, because of the provision of the upperand lower apertures 102 and 50 respectively herein. The adjustment ofthe ball joint 160 and its resilient action is otherwise substantiallythe same as that described above in connectionwith the ball joint 10 ofFigures 1 and 2 and hence requires no additional discussion.

The further modified ball joint, generally designated 120, shown inFigure 5 employs the same socket structure 114 as in the modified balljoint 160 of Figure 4, and the only modification is in the rod and ballunit 122 thereof, particularly in the means by which the ball portion124 is prevented from axial slippage along the rod 126. The latter isprovided with an annular enlargement 128 at approximately the locationcoinciding with the center of the ball portion 124, such as by a coldheating or upsetting process, and the powdered synthetic plasticmaterial of the same kind as that set forth in connection with thediscussion of Figure 4 molded around the enlargement 128 in the samemanner as that also described in connection with Figure 4. Theadjustment of the ball joint is also similar to that of the ball joint100 of Figure 4 in order thatthe spherical outer surface 118 of the ballportion 124 will slip smoothly within the upper and lower socket units32 and 34 as described above in connection with Figure 4, The operationof the ball joint 129 is also substantially identical with thatdescribed above in connection with Figure 4, and hence requires norepetition.

The still further modified ball joint, generally designated=130, shownin Figure 6, differs in construction from the composite ball joint ofFigures 1 and 2 but employs a similar rod-and-ball unit 12 and isgenerally similar with respect to the construction of the sheet metalmember 16 and ring 58, hence similar parts are again designated with thesame reference numerals. In Figure 6, however, the bolts 69 are of theso-called Allen type with hexagonally-socketed heads countersunk intothe ring 58, whereas the sheet metal member 16 and ring 58 have annularrecesses or counterbores 132 and 134. The latter receive the peripheriesof opposed upper and lower conveXo-concave spring washers 136 and 138having central holes 140 and 142 respectively.

The spring washers 136 and 138 are positioned in the recesses 132 and134 with their concave surfaces facing outward away from one another andwith their convex surfaces facing one another. The spring Washers 136and 138 engage radial rim flanges 144 and 146 of upper and lower cuppedapproximately spherical socket shells 148 and 150 of spring steel or thelike. The socket shells 148 and 150 have central socket portions 152 and154 with concave spherical bearing surfaces 153 and 155 engaging androckably receiving the ball portion 24 of the rod-and-ball unit 12. Thesocket portions 152 and 154 are engaged and centered by the edges of thecentral holes 140 and 142 of the washers 136 and 138. The upper socketportion 150 is approximately hemispherical in shape with a small tophole 156 whereas the lower socket portion 152 is in the shape of thezone of a hemisphere with a central hole 158 therein. The hole 158 is ofsufficiently larger diameter than the rod 18 to permit a suflicientlywide angle of rocking of the rod 18 relatively to the central axis ofthe upper and lower socket shells 148 and 150. On the other hand, thehole 158 is smaller than the steel head in order to prevent its jumpingout in the event of disintegration of the ball covering 24.

Mounted in the annular space between the rim flanges 144 and 146 areshims 160, preferably of the peelable laminated type. By this means, thetightness of fit of the ball 24 within the socket shells 148 and 150 iscontrolled independently of the spring load imposed thereon by thespring washers 136 and 138, and can be held substantially constantwithout tightening or loosening with wear. The use of the spring washers136 and 138 also permits building up to a wide variety of modulus curvesof differing characteristics. The spring washers 136 and 138 can also bestacked, or such washers of different thicknesses used, in order to varythe force applied to the socket shells 148 and 150. Moreover, the balljoint 130 is also double-acting, as the axial motion of the rod portion18 of the rod-and-ball unit 12 is springopposed in both upward anddownward directions.

In operation, the still further modified ball joint 130 of Figure 6 actsin a generally similar manner to the ball joint 70 of Figure 3. Theprovision of the counterbores or recesses 132 and 134 for the cuppedspring washers 136 and 138, in cooperation with the edges of theirrespective central holes 140 and 142, automatically centers the upperand lower socket shells 148 and 150 without the need for the spring lugs96 of the ball joint 78 of Figure 3. Furthermore, the provision of theshim or shims 160 enables the tightness of fit of the ball 24 within thesocket shells 148 and 150 to be accurately controlled independently ofthe spring load imposed thereon by the spring washers 136 and 138 andalso to be held substantially constant without tightening or looseningof the ball as a result of wear either of the ball or of the socketshell. While only two cupped spring washers 136 and 138 have been shownin Figure 6, it will be understood that multiples thereof may be used inorder to vary the spring load.

What I claim is:

1. A ball joint for attachment to a support having an aperture with anadjoining abutment surface, said ball joint comprising a pair of cuppedshells of resilient material and of sphere-segment form having concavespherical bearing surfaces facing one another and havingtransversely-projecting rims spaced apart from one another, one of saidshells being mounted in the aperture of the support with its rim spacedapart from the abutment surface thereof, a resilient element disposed inthe space between said last-mentioned rim and the abutment surface, oneof said shells having an opening therein, a ball member disposed betweensaid shells in rocking engagement with said bearing surfaces, anelongated connecting element secured to said ball member and extendingoutwardly through said opening, and means engageable with the rim of theother shell for urging said other shell and said ball member intoyielding engagement with the support-mounted shell.

2. A ball joint for attachment to a support having an aperture With anadjoining abutment surface, said ball joint comprising a pair of cuppedshells of resilient material and of sphere-segment form having concavespherical bearing surfaces facing one another and havingtransversely-projecting rims spaced apart from one another, one of saidshells being mounted in the aperture of the support with its rim spacedapart from the abutment surface thereof, a resilient element disposed inthe space between said last-mentioned rim and the abutment surface, oneof said shells having an opening therein, a ball member disposed betweensaid shells in rocking engagement with said bearing surfaces, anelongated connecting element secured to said ball member and extendingoutwardly through said opening, a second resilient element disposed inengagement with the rim of the other shell on the opposite side thereoffrom the rim of the supportmounted shell, and means engageable with saidsecond resilient element for urging said other shell and said ballmember into yielding engagement with the supportmounted shell.

3. A ball joint according to claim 1, wherein said resilient element isa conveXo-cancave spring washer.

4. A ball joint, according to claim 2, wherein each resilient element isa convexo-concave spring washer, these spring washers having theirconvex surfaces facing one another and engaging thetransversely-projecting rims of their respective shells.

5. A ball joint, according to claim 2, wherein said resilient elementscomprise spring washers having central holes the edges of which engagethe cupped shells in centering relationship therewith.

6. A ball joint, according to claim 1, wherein the opening in said oneshell is of smaller diameter than said ball 7 member whereby to preventaccidental passage of said ball member through said opening.

7. A ball joint, according to claim 1, wherein said ball member is ofcomposite construction with a head and a relatively thin coveringthereover having a spherical outer surface rockably engaging the concavespherical bearing surfaces of said cupped shells, said head being oflarger diameter than the opening in said one shell whereby to preventaccidental passage of said head through said opening in the event ofdisintegration of said covering.

8. A ball joint, according to claim 1, wherein shim means is disposed inthe space between said transverselyprojecting rims of said cupped shellsin abutting engagement with said rims.

9. A ball joint, according to claim 2, wherein shim means is disposed inthe space between said transverselyprojecting rims of said cupped shellsin abutting engagement with said rims.

References Cited in the file of this patent UNITED STATES PATENTS1,499,298 Eller June 24, 1924 2,652,221 Kampa Sept. 15, 1953 2,740,649Latzen Apr. 3, 1956 2,862,740, Alexander Dec. 2, 1958

